Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/26—Phosphates
  • C01B25/32—Phosphates of magnesium, calcium, strontium, or barium
  • C01B25/322—Preparation by neutralisation of orthophosphoric acid
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2/00—Disinfection or sterilisation of materials or objects, in general; Accessories therefor
  • A61L2/02—Disinfection or sterilisation of materials or objects, in general; Accessories therefor using physical processes
  • A61L2/022—Filtration
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B25/00—Phosphorus; Compounds thereof
  • C01B25/16—Oxyacids of phosphorus; Salts thereof
  • C01B25/26—Phosphates
  • C01B25/32—Phosphates of magnesium, calcium, strontium, or barium
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
  • A61L2103/00—Materials or objects being the target of disinfection or sterilisation
  • A61L2103/05—Living organisms or biological materials

Definitions

• the present invention relates to a microbes-removing material which is used for removing bacteria and viruses in the food fermentation industry and in the cultivation and production of biochemical substances, and also for removing bacteria and viruses from body fluids for medical use and from drinking water.
• inorganic porous substances such as silica, activated charcoal and diatomaceous earth
• non-woven fabrics or hollow fibers of organic fibers such as celluloses, polyethylenes and polyesters
• fibrous metal substances of stainless steel, inconel, hastelloy or the like see Japanese Patent Application Laid-Open No. 5-130858.
• porous hydroxyapatite to be obtained from the hard tissue of vertebrates, and hydroxyapatite to be produced by wet processes.
• Calcined hydroxyapatite to be prepared by calcining the above-mentioned hydroxyapatite at a temperature falling between 600°C and 1400°C is also employed as a microbes-removing material.
• microbes-removing materials such as those mentioned above, for example, inorganic substances such as silica, activated charcoal and diatomaceous earth, as being porous, capture microbes in their pores to thereby remove them from the other substances.
• porous, inorganic substances can adsorb microbes of such sizes that can be captured in the pores of the inorganic substances but cannot the other microbes, which therefore shall pass through the inorganic substances together with the processed liquids.
• the adsorption of microbes onto such porous, inorganic substances is not firm, as being mere physical bonding therebetween.
• the adsorption capacity of the porous inorganic substances is small. For these reasons, the porous inorganic substances are not satisfactory for the removal of microbes to purify liquids.
• fibrous filters made of organic polymer fibers of celluloses, polyethylenes, polyesters or the like, or made of stainless steel, inconel, hastelloy or the like, the meshes of the fibrous materials are utilized as sieves. Therefore, such fibrous filters can merely physically fractionate and filter substances of different sizes.
• hydroxyapatite has strong adsorption and separation characteristics specific to particular microbes.
• hydroxyapatite is sensitive to the difference in the functional groups existing on the surfaces of microbes. For these reasons, hydroxyapatite is expected to have good adsorption and separation characteristics specific to the type of microbes.
• hydroxyapatite that has heretofore been used in conventional microbes-separating materials is extracted from natural organisms or is synthesized by wet processes. Hydroxyapatite of this type is poorly crystalline and has poor adsorbability. In addition, it is in the form of fine particles of submicrons. Therefore, it cannot be shaped into filters by itself. If it is used as a microbes-removing material, its liquid permeability could not be ensured.
• Calcined hydroxyapatite to be prepared by calcining wet-process synthesized hydroxyapatite at a temperature falling between 600°C and 1400°C may be used as a microbes-removing material.
• this could not satisfactorily adsorb acidic biochemical substances, namely, acidic microbes, since the growth of the A-plane of each particle crystal structure was not good.
• a microbes-removing material comprising hydroxyapatite having a mean c-axis length of from 1 ⁇ m to 1000 ⁇ m and an aspect ratio of 5 or more.
• the microbes-removing material of the invention comprises hydroxyapatite having a mean c-axis length of from 5 ⁇ m to 200 ⁇ m and an aspect ratio of 10 or more.
• the hydroxyapatite whiskers to be provided herein as the microbes-removing material of the invention have good crystallinity and liquid-permeability.
• the crystalline hydroxyapatite whiskers have high adsorbability with large adsorption capacity and have good adsorption and separation characteristics.
• the microbes-removing material of the present invention comprises hydroxyapatite whiskers, of which the A-planes have been predominantly grown in the c-axis direction, it can remove not only microbes that shall be adsorbed by the whiskers on their C-planes but also those that shall be selectively adsorbed by them onto their A-planes.
• the microbes-removing material of the present invention is sensitive to the difference in the functional groups existing on the surfaces of microbes, and therefore can selectively remove different kinds of microbes.
• the ability of the microbes-removing material of the present invention to selectively remove specific microbes may be for the following reasons:
• the hydroxyapatite, on which the present invention is based, is in the form of hexagonal pillar crystals having crystal planes with different properties, the A-plane corresponding to the side plane and the C-plane corresponding to the bottom plane.
• the A-plane has adsorbing sites (C-sites) composed of positively-charged calcium ions, while the C-plane has adsorbing sites (P-sites) composed of negatively-charged phosphato ions.
• hydroxyapatite whiskers are used in the form of layers or after having been shaped into filters.
• microbes-removing material of the present invention therefore, all microbes which are larger than the pores of the material can be removed as residues, irrespective of the kind of microbes, while the others which are smaller than the pores thereof are selectively adsorbed by hydroxyapatite whiskers onto their adsorbing sites depending on the properties of the functional groups of the microbes.
• the microbes-removing material to be provided by the present invention comprises hydroxyapatite having a mean c-axis length of from 1 ⁇ m to 1000 ⁇ m and an aspect ratio of 5 or more.
• the reason why the mean c-axis length of hydroxyapatite constituting the microbes-removing material of the present invention is defined to fall between 1 ⁇ m and 1000 ⁇ m is because, if the mean c-axis length is smaller than 1 ⁇ m, the material cannot have good liquid permeability, but if it is larger than 1000 ⁇ m, the meshes of the material are too large with the result that almost all microbes pass through such large meshes.
• the reason why the aspect ratio of hydroxyapatite constituting the microbes-removing material of the present invention is defined to be 5 or more is in order to enlarge the adsorbability of hydroxyapatite whiskers on their A-planes.
• the microbes-removing material to be provided by the present invention comprises hydroxyapatite having a mean c-axis length of from 5 ⁇ m to 200 ⁇ m and an aspect ratio of 10 or more.
• the reason why the mean c-axis length of hydroxyapatite constituting the microbes-removing material of the present invention is defined to be preferably not smaller than 5 ⁇ m is in order to ensure the satisfactory liquid permeability of the material; while the reason why it is defined to be preferably not larger than 200 ⁇ m is in order to reduce the number or microbes that may pass through the large meshes due to the c-axis length larger than 200 ⁇ m.
• the reason why the aspect ratio of hydroxyapatite constituting the microbes-removing material of the present invention is defined to be preferably 10 or more is in order to enlarge more the adsorbability of hydroxyapatite whiskers on their A-planes.
• microbes as referred to herein include not only so-called bacteria but also viruses, rickettsiae, chlamydiae, mycoplasmae, spirochaetae, fungi, etc.
• the microbes-removing material of the present invention can be used by itself or after having been formed into layers or filters, to remove microbes.
• the material can be supported by any of non-woven fabrics, cottonlike stuff of natural or synthetic organic fibers, cottonlike stuff of inorganic fibers, or filter cloth or paper made of such fibers.
• the c-axis length and the aspect ratio of this hydroxyapatite were measured with an optical microscope, resulting in that the mean c-axis length was 21 ⁇ m and the mean aspect ratio was 18.
• Test liquids each containing cells of Escherichia coli, Staphylococcus aureus , influenza virus, separately in an amount of 10 6 cells/ml were prepared. 0.1 g of the powdery hydroxyapatite synthesized in the above was added to each test liquid of 4 ml, and fully stirred. These test liquids were left stationary for 10 minutes, and the number of the cells in the resulting supernatant of each test liquid was counted, from which the ability of the hydroxyapatite to adsorb the cells was determined.
• test liquid containing cells of lactic acid bacteria (mean size: 5 ⁇ m), Escherichia coli (mean size: 2 ⁇ m), Staphylococcus aureus (mean size: 0.5 ⁇ m), mycoplasma (mean size: 0.2 ⁇ m) and influenza virus (mean size: 0.1 ⁇ m) in an amount of 10 6 cells/ml each was prepared.
• 10 ml of the test liquid was introduced into each microbes-removing container, at a flow rate of 3 ml/min, and the number of the cells in the resulting filtrate that passed through each container was counted.
• the cellulose filter sample removed the bacteria larger than the filter pore size but could not sufficiently remove the others smaller than the filter pore size.
• the microbes-removing material of the present invention comprises hydroxyapatite having a mean c-axis length of from 1 ⁇ m to 1000 ⁇ m and an aspect ratio of 5 or more, it has good liquid permeability, high microbes-adsorbing power and large adsorption capacity.
• the hydroxyapatite of the invention can efficiently adsorb and remove even acidic microbes.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Inorganic Chemistry (AREA)
• Epidemiology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Animal Behavior & Ethology (AREA)
• General Health & Medical Sciences (AREA)
• Public Health (AREA)
• Veterinary Medicine (AREA)
• Solid-Sorbent Or Filter-Aiding Compositions (AREA)
• Apparatus Associated With Microorganisms And Enzymes (AREA)

Applications Claiming Priority (3)

Publications (3)

Family

ID=17801750

Family Applications (1)

Country Status (4)

Families Citing this family (14)

Citations (3)

Family Cites Families (3)

• 1995
  • 1995-11-13 JP JP29398495A patent/JP3271498B2/ja not_active Expired - Fee Related
• 1996
  • 1996-10-19 EP EP96116824A patent/EP0772975B1/fr not_active Expired - Lifetime
  • 1996-10-19 DE DE69618324T patent/DE69618324T2/de not_active Expired - Lifetime
  • 1996-11-13 US US08/748,614 patent/US5755969A/en not_active Expired - Fee Related

Patent Citations (3)

Also Published As

Similar Documents

Legal Events